From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 28847 invoked by alias); 10 Apr 2006 11:56:04 -0000 Received: (qmail 28817 invoked by uid 48); 10 Apr 2006 11:56:02 -0000 Date: Mon, 10 Apr 2006 11:56:00 -0000 Message-ID: <20060410115602.28816.qmail@sourceware.org> X-Bugzilla-Reason: CC References: Subject: [Bug tree-optimization/23855] loop header should also be pulled out of the inner loop too In-Reply-To: Reply-To: gcc-bugzilla@gcc.gnu.org To: gcc-bugs@gcc.gnu.org From: "rguenth at gcc dot gnu dot org" Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Archive: List-Post: List-Help: Sender: gcc-bugs-owner@gcc.gnu.org X-SW-Source: 2006-04/txt/msg00772.txt.bz2 List-Id: ------- Comment #19 from rguenth at gcc dot gnu dot org 2006-04-10 11:56 ------- So it is indeed chicken and egg ;) load-PRE does not PRE the loads if the loop is not in do-while form, and we won't hoist the loop header copies until the loads are PREd. As to comment #13, if we are able to "clean" the two innermost loops of a nest that is already a good improvement. Though from all the experiments it looks like it is advisable to write do-while loops with hoisted loop header copies manually rather than for loops. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23855